1. Field of the Invention
This invention relates to a dampening water regulating scale, and a dampening water control method using the dampening water regulating scale.
2. Description of the Related Art
In a lithographic printing that uses dampening water, the feed rate of dampening water is known to influence print quality. In actual practice, generally, an experienced operator visually checks prints, and empirically determines a feed rate of dampening water. In one conventional technique, a film thickness of dampening water on the surface of a printing plate or a dampening water roller is measured, and control is carried out to maintain the film thickness constant.
In view of the above situation, Applicants herein have proposed a dampening water control method for printing, along with a subject image, detecting patches that show density variations occurring with variations in dampening water, and controlling the feed rate of dampening water while measuring densities of the detecting patches (e.g. Japanese Unexamined Patent Publication No. 2002-355950).
The above dampening water control method is capable of automatically controlling the feed rate of dampening water by measuring the densities of the detecting patches. This assures a proper feed rate of dampening water without relying on the operator's experience. However, the above prior method still requires the operator to determine visually the propriety of the feed rate of dampening water during a printing operation.